The invention relates to a plug-in coupling for connecting pipelines, tubes or the like, having a valve body which is disposed in one of the two coupling parts and can be actuated from the outside, in particular by a hand lever, and having a locking sleeve which can be displaced from a locking position, in which the plugged-together position of the two coupling parts is secured by spring loading, into a release position, and having a further valve body, which is disposed in the other coupling part.
It is an object of the invention to provide a plug-in coupling of the above-mentioned type in an operationally reliable and easy-to-operate manner.
This object is achieved in the case of a plug-in coupling having the above-mentioned features it being provided that, in the plugged-together position, the one valve body brings about primarily opening of the other valve body at the periphery. A pressure-neutral coupling is thus provided even in the case of high media pressures, actuation correspondingly requiring only moderate forces. The valve body which releases the flow path is not displaced primarily in the axial direction, but rather is raised with tilting action. Even just small tilting angles are sufficient here. All of this also takes place in a sealed situation, with the result that it is possible to operate with minimal leakage. In this respect, excellent operational reliability is provided.
Taking the safety aspect into consideration, the invention also proposes observing a corresponding actuating sequence. This is embodied in a plug-in coupling wherein the external actuation of the valve body in a release position of the locking sleeve, which is retained there despite the spring loading, and displacement of said locking sleeve into the release position in an open position of the valve body are blocked. In this way, a plug-in coupling with a high safety value is achieved. The valve body can only be opened in the coupled position of the coupling parts. In contrast, decoupling can only be carried out when the valve body is located in the closed position. The hand lever cannot be actuated as long as the locking sleeve is located in a release position. Conversely, the locking sleeve cannot be brought out of its locking position if the hand lever is not in the definitive blocking position. Such a rigid progression in conjunction with the hand-lever-actuatable plug-in coupling means that the latter can be used for problematic areas, such as chemistry and pharmaceuticals. It thus also proves advantageous for the two blocking positions to be associated with the end regions of the displacement of the locking sleeve and external actuation. It is only at the very last moment that the respective function is activated. This presupposes that the actuating travel is complete in each case. It is the case therefore that no overall volume compression is present. The locking takes place first of all, and then the valves are opened. It is further provided for the external actuation to take place by means of a rotary actuation which is converted into a longitudinal displacement of the valve body. The drive in this respect requires only a small number of parts, and is reliable, if it is further provided such that the rotary-actuation axis has an eccentric on which the valve body is articulated via connecting-rod bearings, forming an anchoring point. In order to facilitate the valve body in finding its valve seat of its own accord in practice, the invention proposes that, in a position in which it has been displaced in an opening direction, the valve body is mounted such that it can be pivoted about its anchoring point on the rotary-actuation axis. An advantageous embodiment of the rotary-actuation axis as far as the activation-related interaction with the locking sleeve is concerned is achieved by the rotary-actuation axis carrying a semicircularly-shaped locking protrusion which is located concentrically with the axis and with which a guide slot of the locking sleeve is associated, such that, in a release position of the locking sleeve, the semicircular profile of the locking protrusion enters into the guide slot with engagement on both sides and, in a release position of the locking sleeve, the arcuate surface of said semicircular profile, entering into a free space, moves into the guide slot, in front of a blocking flank of the guide slot, to the side of the guide slot. The blocking and release operations of the rotary-actuation axis are thus clearly separate. An advantageous feature then resides in the fact that the locking sleeve itself is secured against rotation by the rotary-actuation axis. This also provides high-grade functional reliability of the plug-in coupling. Provision is also made for the rotary-actuation axis to continue into a preferably removable hand-lever grip. With a fixedly associated hand-lever grip, safety is aided here by the hand-lever grip having a predetermined breaking point. The safety idea is further embodied by the hand-lever grip being provided with a catch. In using the catch movement, an advantageous embodiment resides in the fact that the actuation path of the catch can be blocked via a lead-seal device. It is possible to achieve long service lives for the sealing bodies by the plug-in end of the valve body being drawn against a seat seal by way of a curved rear side. In this case, the sealing seat is facilitated by the seat seal being disposed in a sliding sleeve which is spring-loaded in a sealing direction. The sealing engagement of said sliding sleeve may also be assisted by the media pressure. Access is taken into account for this purpose. A measure which avoids friction and thus premature wear at the same time is also achieved in that, at its end which is directed away from the sealing seat, an annular seal is associated with the sliding sleeve, which seal, being in positive engagement with the sliding sleeve and the coupling-part housing, compensates for the movement of the sliding sleeve by itself deforming. It is further provided for the sliding sleeve to engage against the rear side of the valve body. Moreover, it is favorable if, on its plug-in-side head surface, the sliding sleeve carries a second seat seal for interaction with the head surface of the other coupling part, that is to say the plug-in nipple.
A development of this provides for the head surface of the plug-in-nipple coupling part to be curved to match a correspondingly curved recess of the valve body of the coupling. In this case, a shaping has proven advantageous to the effect that the curved configuration of the head surface is made up of a central ball portion with an adjoining shallow truncated cone. This has excellent centering action in respect of the pivotable mounting of the valve body. It is also taken into account that, in a plugged-in position, the curved head surface is located at a small spacing from the seat seal of the sliding sleeve associated with it. This allows mechanical coupling without loading of the head surface. On the other hand, however, the spacing is small enough to prevent any dead space remaining in which medium could accumulate to any appreciable extent. It is also favorable, during its opening displacement, for the valve body to push the head surface back in relation to the encircling front surface of the plug-in nipple, with opening for throughflow of media being effected as a result of the valve body moving into an opening of the front surface of the plug-in nipple. This takes place without great force being applied. Furthermore, a solution which is even important in its own right consists in that the front surface in the sleeve-like housing of the plug-in-nipple coupling part, following an unlocking operation, can be displaced beyond the plug-in-side front wall of the plug-in-nipple housing. This allows easy access for cleaning. For forward and rearward displacement in this respect, provision is made for the locking and unlocking to take place by means of an actuating ring which is disposed on the sleeve-like housing of the plug-in-nipple coupling part in a rotatable manner and to the rear of an annular groove, into which the blocking balls, controlled by the locking sleeve, enter. This allows the head surface to be drawn in again extremely easily, i.e. displaced back into a protected position within the housing of the plug-in-nipple coupling part. It is only in this position, which ensures sufficient plug-in guidance for the coupling, that the valve body of the plug-in nipple can be opened. The forward displacement of the head surface beyond the encircling front surface allows not just the easy cleaning of the plug-in nipple; it also allows the state of the same to be checked. It is further provided for the curved head surface to be seated on a resiliently mounted load-bearing part which can be displaced, with circumferential guidance, in the housing of the plug-in-nipple coupling part.
An advantageous configuration is also achieved by a dummy stopper which is associated with the plug-in-nipple coupling part and has a sleeve wall engaging over it in a cup-like manner, a seat seal of the dummy stopper engaging against the encircling front surface and the dummy stopper being provided with retaining balls which can be directed into the annular groove of the housing by screw-action displacement of the cup sleeve wall in relation to an inner sleeve. This solution embodies advantageous securing for transportation with simultaneous protective covering of the load-bearing part, which is always located in a somewhat exposed position. In order that the arrangement can be easily secured for transportation, providing a sufficiently pressure-tight protective cap in the direction of the plug-in nipple, provision is made for the cup sleeve wall and inner sleeve to be provided with gripping ribs.
A further advantageous measure is provided by a closure stopper which is retained by the blocking balls, is similar to a plug-in nipple and blocks the locking sleeve against further displacement shortly before said locking sleeve reaches its securing end position, that is to say the plugged-together position. This is an advantage from the solution where the blocking positions are only achieved at the last moment. The construction is then characterized by a stop-limited clearance between the sliding sleeve and the guiding housing of the same in the region of a spring chamber, which is a constituent part of the two parts and accommodates a prestressed sliding-sleeve spring. This is achieved structurally by simple means in that, in a supported position of the valve body, the sliding-sleeve spring is supported on an annular shoulder of the housing, another annular shoulder of the sliding sleeve trailing in relation to the same to provide a clearance. It is also proposed that, directed away from the coupling joint, the sliding sleeve has a flexible corrugated-tube portion which interacts with the annular seal. This functions, at the same time, as the sliding-sleeve spring.
Taking up the idea of the primarily occurring peripheral opening of the other valve body, it is proposed that the other valve body can be displaced both with tilting movement and also axially in the other coupling part. The tilting movement can be achieved by corresponding shaping of the contact surfaces of the valve bodies. Furthermore, the other valve body is mounted by being supported by means of a helical spring. This brings with it from the movement point of view, the, so to speak, floating movement of said valve body to good effect. The helical spring is preferably a conical helical spring. It is also proposed that the valve body be accommodated in a cylindrical valve seat with which, on the valve-seat side, a radial seal is associated. The tilting can also be brought about, however, utilizing the above-explained drive means of the rotary-actuation axis, which displaces one valve body as initiator in the coupling. This makes it possible to achieve the situation where the axis of the one valve body, at the beginning of the opening movement, moves into a tilted position which does not coincide with the longitudinal center axis of the coupling, said axes finally being oriented in coaxial alignment. The connecting-rod drive is thus utilized here to very good effect. Accordingly, the valve body, when in aligned orientation with the longitudinal center axis of the coupling, has a closure edge running perpendicularly to the longitudinal center axis. The opening path, which begins with a minimal, approximately half-moon-shaped initial slit, finally increases into a rotationally symmetrical equal-width annular gap for the medium.
A further measure for achieving the sought-after operational reliability consists in the shaft being secured beneath an end bushing by a retaining ring, and in that the retaining ring, for its part, is secured by a securing bushing engaging radially over it. In order that the securing bushing, which may optionally be screw-connected, remains retained in non-releasable manner, it is proposed that the securing bushing itself be secured on the shaft by a split pin.
In order to maintain disruption-free actuation of the control device, it is proposed that the connecting-rod bearing has a plastics-material sliding element. This may be a lining ring, with the result that the sliding element is of ring-like formation all the way round.
The sliding element is provided in pairs. A low-wear solution is preferred as far as the sliding elements are concerned, for which purpose said elements are formed from fiber-reinforced Teflon.
The invention then proposes that the removable hand-lever grip has a wrench head which can be connected to a socket portion for driving the shaft in rotation. A hand lever configured in this way can be stored, following the activation of the coupling, in various places, if appropriate so as to ensure authorization. It may be provided to be of a size such as to allow easy actuation; following removal, on the other hand, it does not get in the way. In terms of rotation, the full 180xc2x0 are also utilized here for the activation of the connecting-rod mechanism. In the case of larger installations for such couplings, it is advantageous for a locking sleeve to have a freely projecting gripping ring which runs substantially transversely to the longitudinal center axis of the coupling.
As far as the seal is concerned, it is also proposed for the annular seal of the sliding sleeve to have an O-ring mounted upstream of it on the coupling-joint side. It is advantageous in this case for the downstream annular seal to be a U-ring with a U-opening in the direction of the medium. Utilizing the media pressure, it is thus possible, with the sealing bodies being subjected to extremely low mechanical stressing, to increase the sealing action. These may also be used advantageously on the shaft side.